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Archived

Avalanche Forecast

Dec 27th, 2013–Dec 28th, 2013
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Northwest Inland.

Confidence

Poor - Due to the number of field observations

Weather Forecast

Saturday: Cloudy with flurries or periods of snow developing later in the day – 5-10 cm. The freezing level is at valley bottom and winds are light to moderate from the west-southwest. Sunday: Mainly cloudy with a chance of flurries. The freezing level is near valley bottom but there is a chance of an above freezing layer near 1500 m. Winds are light from the W-SW. Monday: Periods of snow. The freezing level is near valley bottom and winds are light to moderate from the SW.

Avalanche Summary

No new avalanches have been reported, but observations are very limited. Areas with heavier recent snowfall likely experienced a natural avalanche cycle on Thursday. Rider triggering remains a concern in steeper terrain and wind loaded features, primarily at and above treeline.

Snowpack Summary

Storm snow totals in the region are around 40-50 cm, with moist or wet snow below treeline. Periods of moderate to strong W-SW winds were likely over the past couple days. Expect dense wind slabs in exposed lee terrain and cross-loaded features. Between 40 and 80 cm of snow sits on a crust that extends up to treeline and possibly beyond. This interface was "popping" under easy loads in snowpack tests a few days ago. A new surface rain crust will probably form at lower elevations as temperatures cool tonight. Deeper in the snow pack a layer of facets/surface hoar formed in early December can be found in the top 100cm in the Ashman. The mid and lower snowpack is still structurally weak and faceted. Depth hoar and an early season crust exist near the ground.

Avalanche Problems

Storm Slabs

It may be possible to trigger fresh storm and wind slabs, particularly in steep exposed N-E facing terrain, where wind loading has occurred, and at high elevations, where a surface rain crust is absent.
Choose conservative lines and watch for clues of instability.>The new snow will require several days to settle and stabilize.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 4

Persistent Slabs

There is not much news on the buried mid-December rain crust. Watch for clues of instability and be prepared to dig and investigate if you plan on venturing into more committing terrain.
Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 5